The present invention relates to optical fiber communication systems and more particularly to a safety interlocked high power fiber system using an OTDR.
Fiber optic technology has evolved significantly since the invention of the laser. Semiconductor lasers, fiber and devices have been continuously improved in support of increasingly sophisticated fiber communication systems. For some time, practical fiber communication systems employed optical power levels less than 10 mW. A new generation of lasers and devices are now capable of producing much greater power.
Semiconductor laser diodes once capable of producing only a few milliwatts of optical power now can deliver several hundred milliwatts. These high power Class IV lasers can be used individually or in combination to pump rare-earth doped fiber amplifiers and fiber lasers to yield more than a watt of infrared coherent fiber-coupled power.
To practically realize high power fiber transmission systems, one problem which must be addressed is the safe deployment of high power carrying fibers. Industry standards and laws of certain countries prohibit the operation or installation of Class IV laser systems without some type of interlocking safety system to prevent inadvertent release of high energy optical levels from the laser. To Applicant's knowledge, no exclusion exists specifically for closed fiber transmission systems. In the event of a fiber break in a high power fiber transmission system, the harmful laser emissions from the broken fiber pose an extreme hazard and can cause severe injuries such as burnt retinas or damage to other living tissues and may cause fires or other property damage. In addition, pumping a high powered laser into a system having broken fiber can severely damage the optical fiber system due to fiber fusion. For many reasons, therefore, it is important to shut down a high power laser as soon as possible after a break or fault occurs in the extended fiber system. No safety systems exist for use in an extended fiber system for automatically shutting down the high power laser when there is a break in the fiber.
Therefore, a need exists for a safety interlocking system that interlocks with the high power laser for automatically shutting down or disabling the laser when a fault or break is detected in an extended fiber system.